This specification generally relates to systems and techniques for a user interface tab bar control affordance for a mobile computing device.
In some implementations, it is advantageous to protect an underlying application running on a mobile computing device from receiving accidental user input. For example, user input can be received from a keyboard, pointing device, or on-screen contact with a touchscreen included with the mobile computing device. The user may place the mobile computing device in a location that may inadvertently provide erroneous input to the device (e.g., the user places the device in a pocket, backpack, or handbag). Locking the mobile computing device can prevent the occurrence of the accidental input as the computing device can ignore any user input it receives while in a locked state.